fettle-mcp

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Update a maintenance window

update_maintenance_window

Idempotent

Update a maintenance window's name, schedule, scope, or monitors, or disable it to silence alerts. Only passed fields change; monitors stay checked.

Instructions

Change one maintenance window's name, schedule, scope or monitors, or switch it off with enabled false; only the fields you pass change. While a window is in effect its monitors keep being checked, but no incident opens and no alert goes out. A recurring window cannot become one-time: delete it with delete_maintenance_window and create a new one. Check a new schedule with preview_maintenance_window first. Requires a key with the write scope. An invalid argument is a 422 and a resulting schedule that is invalid (for example a bad rrule) a 406, each with the reason. Returns the window. Example: {"window_id": "", "enabled": false}

Input Schema

TableJSON Schema

Name	Required	Description
`name`	No	Display name, 1 to 255 characters.
`rrule`	No	Repeats the window: one iCal RRULE without the RRULE: prefix, at most 1024 characters, for example FREQ=WEEKLY;BYDAY=SU;BYHOUR=3. Hourly, minutely and secondly frequencies are refused.
`scope`	No	ORG covers every monitor of the organization and ignores monitor_ids; MONITOR covers only monitor_ids.
`dtstart`	No	The first start, an ISO 8601 date-time in the wall-clock time of timezone, for example 2026-10-14T22:00:00. A UTC offset or Z is a 422.
`enabled`	No	false keeps the window but stops it silencing alerts.
`timezone`	No	IANA zone name such as Europe/Berlin, at most 64 characters. The schedule repeats in it, so a weekly 03:00 stays 03:00 across daylight-saving changes.
`window_id`	Yes	The window's uuid from list_maintenance_windows. An id that is not a window of this organization is a 404.
`monitor_ids`	No	Replaces the list when passed. Monitor uuids from list_monitors, at least one when scope is MONITOR. An id that is not a monitor of this organization is a 404.
`duration_minutes`	No	How long each occurrence lasts, 1 to 40320 minutes.

Output Schema

TableJSON Schema

Name	Required	Description
`id`	Yes
`name`	Yes
`rrule`	Yes
`scope`	Yes	Known values: MONITOR, ORG.
`dtstart`	Yes
`enabled`	Yes
`timezone`	Yes
`created_at`	Yes
`monitor_ids`	No
`duration_minutes`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed10 schema fields changedv0.6.1Oct 20, 2026

addedInput schema / properties / dtstart / description

Added value: +"The first start, an ISO 8601 date-time in the wall-clock time of timezone, for example 2026-10-14T22:00:00. A UTC offset or Z is a 422."

addedInput schema / properties / duration_minutes / description

Added value: +"How long each occurrence lasts, 1 to 40320 minutes."

addedInput schema / properties / enabled / description

Added value: +"false keeps the window but stops it silencing alerts."

addedInput schema / properties / monitor_ids / description

Added value: +"Replaces the list when passed. Monitor uuids from list_monitors, at least one when scope is MONITOR. An id that is not a monitor of this organization is a 404."

addedInput schema / properties / name / description

Added value: +"Display name, 1 to 255 characters."

addedInput schema / properties / rrule / description

Added value: +"Repeats the window: one iCal RRULE without the RRULE: prefix, at most 1024 characters, for example FREQ=WEEKLY;BYDAY=SU;BYHOUR=3. Hourly, minutely and secondly frequencies are refused."

addedInput schema / properties / scope / description

Added value: +"ORG covers every monitor of the organization and ignores monitor_ids; MONITOR covers only monitor_ids."

addedInput schema / properties / timezone / description

Added value: +"IANA zone name such as Europe/Berlin, at most 64 characters. The schedule repeats in it, so a weekly 03:00 stays 03:00 across daylight-saving changes."

addedInput schema / properties / window_id / description

Added value: +"The window's uuid from list_maintenance_windows. An id that is not a window of this organization is a 404."

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "created_at": {
+      "type": "string"
+    },
+    "dtstart": {
+      "type": "string"
+    },
+    "duration_minutes": {
+      "type": "integer"
+    },
+    "enabled": {
+      "type": "boolean"
+    },
+    "id": {
+      "format": "uuid",
+      "type": "string"
+    },
+    "monitor_ids": {
+      "items": {
+        "format": "uuid",
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "name": {
+      "type": "string"
+    },
+    "rrule": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "scope": {
+      "description": "Known values: MONITOR, ORG.",
+      "type": "string"
+    },
+    "timezone": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "id",
+    "name",
+    "enabled",
+    "scope",
+    "dtstart",
+    "duration_minutes",
+    "rrule",
+    "timezone",
+    "created_at"
+  ],
+  "type": "object"
+}

First observedv0.5.4Oct 20, 2026

TDQS

A4.8/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations: reveals auth requirement (write scope), the side effect while a window is in effect (monitors still checked but no incident opens and no alert fires), the recurrence-immutability constraint, and error semantics (422 invalid argument, 406 invalid resulting schedule, each with a reason). None of this is derivable from readOnlyHint/idempotentHint/destructiveHint.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the action, and nearly every clause carries non-obvious information (partial update, silencing behavior, recurrence constraint, preview step, auth scope, error codes, return, example). The middle is a dense semicolon run-on that could be split into bullets, which is the only reason this is not a 5.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 9-parameter mutation tool with an output schema, the description covers everything an agent needs: mutation semantics, side effects, prerequisites, auth, failure modes, and a concrete invocation example. Return-value detail is correctly left light since an output schema exists.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description adds value: it clarifies that every field other than window_id is optional and only supplied fields change, which reframes the 9-property schema as a patch. The worked example {"window_id": ..., "enabled": false} demonstrates that partial-update pattern concretely.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource (change one maintenance window's fields or disable it) and enumerates the editable dimensions (name, schedule, scope, monitors, enabled). An agent can distinguish it from create_maintenance_window, delete_maintenance_window, get/list_maintenance_window and preview_maintenance_window without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit when-to-use and when-not-to-use: recurring windows cannot be converted to one-time, so delete with delete_maintenance_window and recreate; validate a new schedule with preview_maintenance_window first. It also states the partial-update condition (only passed fields change). Alternatives and prerequisites are named outright.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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